Better Living Through Technology!

Main menu

Post navigation

Why Are Captchas Case Sensitive?

Why is it so many captchas are case sensitive – does it really matter if I enter ‘E’ or ‘e’?

As well, have you noticed how often the letters are uppercase, so not only do you need to fiddle with the captchas in the first place, but you have to hit the Shift key?

Why not use lowercase? After all, if programmers made either way valid, do the spammers REALLY win? It’s a ridiculous set of hoops to jump through just to prove your humanity, and realistically it’s only a matter of time before spambots get smart enough to defeat them – and then what? Captchas using microphones and voice recognition? The scanning of human eyes?

It seems like any Captcha is a poor method of identifying someone’s humanity, one that irritates them to the point they just leave the site. So whether you’re the sysadmin for a large forum community or someone who’s setting up an online store, stop and think for a moment – is a Captcha going to help you avoid spammers registering for a user account, or will it stop EVERYONE from registering?

There are countless alternatives, and given the rate that spammers seem to be bypassing Captcha requests anyways, it might be worth considering those alternatives instead.

But if you do use a Captcha, at least consider letting lowercase and uppercase both succeed: The fact is, if you include upper- and- lowercase, and digits, you’re looking at 26+26+10=62 possibilities per character, instead of 26+10=36 if lowercase and uppercase case are allowed – almost 50% fewer choices. The solution? Just add a character!

Here’s the math: a 4-character case sensitive code has 14 million possibilities – but a 5 character case-insensitive one has SIXTY MILLION.

Computers are supposed to make it easier for us, so is it really a security issue that forces me to remember the Shift key when typing in captchas – or programming laziness?

2 thoughts on “Why Are Captchas Case Sensitive?”

I don’t think there is any easy way – ideally, the site should mention it. At the very least, it would be great if everyone went with case insensitive capthcas – that way, if someone made a mistake in lowercase/uppercase, it would still work.